Cosmetic skin care compositions containing branched esters for controlling sebum/oil on human skin and improving or preventing the appearance of aged skin.
Cosmetic products which improve the appearance of skin are increasingly popular with consumers. Frequently, consumers seek to alleviate or delay the signs of aged or photoaged skin, such as fine lines and wrinkles, dry and sagging skin. Consumers also seek other benefits in addition to anti-aging.
A frequent, undesirable skin condition is xe2x80x9coily skin,xe2x80x9d the condition which results from the excessive amount of sebum on the skin. Sebum is skin oil which is produced by sebocytes (cells of the sebaceous glands in the skin) and is then secreted to the skin surface. Oily skin is associated with a shiny, undesirable appearance and a disagreeable tactile sensation. Oily skin affects various age groups. Cosmetic products which provide both sebum control and anti-aging benefits are highly desirable.
Several patents disclose the use of branched alcohols in cosmetic compositions. See for instance U.S. Pat. No. 4,496,536 (Moller et al.), U.S. Pat. No. 5,093,112 (Birtwistle et al.), and U.S. Pat. No. 5,344,850 (Hata et al.).
Unfortunately, alcohols, whether branched or not, have a sharp unpleasant odor and thus present a formulation challenge for a cosmetic chemist. The esterification of alcohols changes their odor, but not necessarily for the better.
Cosmetic compositions containing branched esters are also known. U.S. Pat. No. 5,489,426 (Zabotto et al.) describes cosmetic composition containing branched alkyl esters, wherein the branched hydrocarbon chain contains from 3 to 20 carbon atoms. U.S. Pat. No. 5,578,299 (Starch) describes cosmetic rinse-off compositions containing 49-98% of mineral oil and, optionally, a branched chain alcohol ester as an emollient. U.S. Pat. No. 5,658,580 (Mausner) describes anti-sebum compositions containing selected neopentanoate esters to smooth the skin. U.S. Pat. No. 5,773,015 (Bajor et al.) describes anti-sebum compositions containing C11-C30 esters of salicylic acid. U.S. Pat. No. 5,849,273 (Bonda et al.) describes a sunscreen composition containing an alkyl salicylate ester and, optionally, an alkyl benzoate ester; both esters contain a single-branched alkyl, the branch consisting of butyl, or hexyl or octanoyl alkyl radical.
The present invention is based, at least in part, on the discovery of branched esters that have a pleasant scent and also are effective sebum suppressors. It has been iscovered, as part of the present invention that esters of straight chain alcohols are not effective and that not all branched chain alcohol esters are either effective or have a pleasant scent.
The present invention includes a skin care cosmetic composition comprising:
(i) from about 0.001% to about 50% of a branched chain ester RCOORxe2x80x2, wherein R is selected from the group consisting of CH3, phenyl, and CH3(CH2)4CHxe2x95x90CHCH2CHxe2x95x90CH(CH2)7; and Rxe2x80x2 is a methyl-branched hydrocarbon radical containing a total of at least 6 carbons, provided that if Rxe2x80x2 contains more than 6 carbons total, the branched ester contains more than one methyl group; and
(ii) a cosmetically acceptable vehicle.
The present invention also includes a method of controlling or preventing an oily skin condition, especially in the facial area, by applying to the skin a composition from about 0.001% to about 100% of the branched ester as described above.
The invention also includes a cosmetic method of reducing, preventing or controlling sebum secretion from sebocytes by applying a composition comprising from about 0.001% to about 100% of the branched ester.
The invention also includes a cosmetic method of stimulating collagen and glycosaminoglycan synthesis by fibroblasts in the skin, by applying a composition comprising from about 0.001% to about 100% of the branched ester.
The invention also includes a cosmetic method of treating or delaying chronoaged, photoaged, dry, lined or wrinkled skin, shielding the skin from harmful UVA and UVB light (sunscreening), increasing stratum corneum firmness and flexibility, and generally increasing the quality of skin by applying to the skin the inventive composition.
The inventive methods and compositions provide control of sebum secretion from sebocytes, improved oil control and improved skin feel, prevent shine and stickiness, while also providing anti-aging benefits which results in reduced appearance of wrinkles and aged skin, improved skin color, treatment of photoaged skin, improvement in skin""s radiance and clarity and finish, and an overall healthy and youthful appearance of the skin.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word xe2x80x9cabout.xe2x80x9d All amounts are by weight of the oil-in-water emulsion, unless otherwise specified.
The term xe2x80x9cskinxe2x80x9d as used herein includes the skin on the face, neck, chest, back, arms, hands and scalp.
The inventive methods and compositions include a branched chain ester RCOORxe2x80x2 wherein R is selected from the group consisting of: (acetate esters), phenyl (benzoate esters), and CH3(CH2)4CHxe2x95x90CHCH2CHxe2x95x90CH(CH2)7 (linoleate esters); and Rxe2x80x2 is a branched aliphatic hydrocarbon radical containing a total of at least 6 carbon atoms and containing solely methyl branches, provided that if Rxe2x80x2 contains more than 6 carbons total, the branched ester contains more than 1 methyl group.
Preferably Rxe2x80x2 contains from 6 to 20 carbons, most preferably from 10 to 13 carbons, to attain optimum efficacy. The preferred esters are selected from linoleate esters due to their optimum performance.
The alcohol, which serves as a starting material for the ester, may contain a mix of various chain lengths"" alcohols and various branches. Such mixed alcohol is suitable for use in the present invention, as long as the predominant alcohol in the mix contains a total of at least 6 carbon atoms and methyl branching
The ester is employed in the inventive methods in an amount of from 0.001% to about 100%, preferably from 0.1% to 20%, most preferably from 0.1% to 10%.
The branched esters within the scope of the invention are commercially available, e.g. from Exxon (under Exxate(copyright) trademark) or may be synthesized in accordance with the procedures in Example 1.
The preferred inventive compositions and methods also include an oil-absorbing powder. Examples of suitable oil-absorbing powder include but are not limited to silica (preferably fumed), talcum, and clay. The preferred oil-absorbing powder is fumed silica, due to its superior oil-absorbing capacity.
The oil-absorbing powder provides an immediate sebum control, but not a long-term relief, since it cannot be used in large amounts without whitening the skin. According to the present invention, the oil-absorbing powder may be present in an amount of no greater than 1%, generally from 0.01% to 1%, preferably from 0.1% to 1%, most preferably from 0.5% to 1%.
Although the branched esters employed in the inventive methods and compositions are liquid, and thus the invention is effective even in the absence of the carrier, the compositions according to the invention comprise a cosmetically acceptable vehicle to act as a diluant, dispersant or carrier for branched ester so as to facilitate their distribution when the composition is applied to the skin.
The vehicle may be aqueous, anhydrous or an emulsion. Preferably, the compositions are aqueous or an emulsion, especially water-in-oil or oil-in-water emulsion. Water when present will be in amounts which may range from 5 to 99%, preferably from 40 to 90%, optimally between 60 and 90% by weight.
Besides water, relatively volatile solvents may also serve as carriers within compositions of the present invention. Most preferred are monohydric C1-C3 alkanols. These include ethyl alcohol, methyl alcohol and isopropyl alcohol. The amount of monohydric alkanol may range from 1 to 70%, preferably from 10 to 50%, optimally between 15 and 40% by weight.
Emollient materials may also serve as cosmetically acceptable carriers. These may be in the form of silicone oils and synthetic esters. Amounts of the emollients may range anywhere from 0.1 to 50%, preferably between 1 and 20% by weight.
Silicone oils may be divided into the volatile and non-volatile variety. The term xe2x80x9cvolatilexe2x80x9d as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5, silicon atoms. Linear volatile silicone materials generally have viscosities less than about 5 centistokes at 25xc2x0 C. while cyclic materials typically have viscosities of less than about 10 centistokes. Nonvolatile silicone oils useful as an emollient material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The essentially non-volatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from about 5 to about 25 million centistokes at 25xc2x0 C. Among the preferred non-volatile emollients useful in the present compositions are the polydimethyl siloxanes having viscosities from about 10 to about 400 centistokes at 25xc2x0 C.
Among the ester emollients are:
(1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples thereof include isoarachidyl neopentanoate, isononyl isonanonoate, oleyl myristate, oleyl stearate, and oleyl oleate.
(2) Ether-esters such as fatty acid esters of ethoxylated fatty alcohols.
(3) Polyhydric alcohol esters. Ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, pplyglycerol poly-fatty esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters.
(4) Wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate and arachidyl behenate.
(5) Sterols esters, of which cholesterol fatty acid esters are examples thereof.
Fatty acids having from 10 to 30 carbon atoms may also be included as cosmetically acceptable carriers for compositions of this invention. Illustrative of this category are pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic and erucic acids.
Humectants of the polyhydric alcohol type may also be employed as cosmetically acceptable carriers in compositions of this invention. The humectant aids in increasing the effectiveness of the emollient, reduces scaling, stimulates removal of built-up scale and improves skin feel. Typical polyhydric alcohols include glycerol, polyalkylene glycols and more preferably alkylene polyols and their derivatives, including propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, ethoxylated glycerol, propoxylated glycerol and mixtures thereof. For best results the humectant is preferably propylene glycol or sodium hyaluronate. The amount of humectant may range anywhere from 0.5 to 30%, preferably between 1 and 15% by weight of the composition.
Thickeners may also be utilized as part of the cosmetically acceptable carrier of compositions according to the present invention. Typical thickeners include crosslinked acrylates (e.g. Carbopol 982), hydrophobically-modified acrylates (e.g. Carbopol 1382), cellulosic derivatives and natural gums. Among useful cellulosic derivatives are sodium carboxymethylcellulose, hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl cellulose and hydroxymethyl cellulose. Natural gums suitable for the present invention include guar, xanthan, sclerotium, carrageenan, pectin and combinations of these gums. Amounts of the thickener may range from 0.0001 to 5%, usually from 0.001 to 1%, optimally from 0.01 to 0.5% by weight.
Collectively, the water, solvents, silicones, esters, fatty acids, humectants and/or thickeners will constitute the cosmetically acceptable carrier in amounts from 1 to 99.9%, preferably from 80 to 99% by weight.
An oil or oily material may be present, together with an emulsifier to provide either a water-in-oil emulsion or an oil-in-water emulsion, depending largely on the average hydrophilic-lipophilic balance (HLB) of the emulsifier employed.
Surfactants may also be present in cosmetic compositions of the present invention. Total concentration of the surfactant will range from 0.1 to 40%, preferably from 1 to 20%, optimally from 1 to 5% by weight of the composition. The surfactant may be selected from the group consisting of anionic, nonionic, cationic and amphoteric actives. Particularly preferred nonionic surfactants are those with a C10-C20 fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobe; C2-C10 alkyl phenols condensed with from 2 to 20 moles of alkylene oxide; mono- and di-fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, mono- and di-C8-C20 fatty acids; block copolymers (ethylene oxide/propylene oxide); and polyoxyethylene sorbitan as well as combinations thereof. Alkyl polyglycosides and saccharide fatty amides (e.g. methyl gluconamides) are also suitable nonionic surfactants.
Preferred anionic surfactants include soap, alkyl ether sulfate and sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates, C8-C20 acyl isethionates, acyl glutamates, C8-C20 alkyl ether phosphates and combinations thereof.
Various types of additional active ingredients may be present in cosmetic compositions of the present invention. Actives are defined as skin benefit agents other than emollients and other than ingredients that merely improve the physical characteristics of the composition. Although not limited to this category, general examples include additional anti-sebum ingredients and sunscreens.
Preferred additional anti-sebum ingredient is a retinoid. The term xe2x80x9cretinoidsxe2x80x9d as used herein includes retinoic acid, retinol, retinal and retinyl esters.
The term xe2x80x9cretinolxe2x80x9d includes the following isomers of retinol: all-trans-retinol, 13-cis-retinol, 11-cis-retinol, 9-cis-retinol, 3,4-didehydro-retinol. Preferred isomers are all-trans-retinol, 13-cis-retinol, 3,4-didehydro-retinol, 9-cis-retinol. Most preferred is all-trans-retinol, due to its wide commercial availability.
Retinyl esters suitable for use in the present invention are C1-C30 esters of retinol, preferably C2-C20 esters, and most preferably C2, C3, and C16 esters because they are more commonly available. Examples of retinyl esters include but are not limited to: retinyl palmitate, retinyl formate, retinyl acetate, retinyl propionate, retinyl butyrate, retinyl valerate, retinyl isovalerate, retinyl hexanoate, retinyl heptanoate, retinyl octanoate, retinyl nonanoate, retinyl decanoate, retinyl undecandate, retinyl laurate, retinyl tridecanoate, retinyl myristate, retinyl pentadecanoate, retinyl heptadeconoate, retinyl stearate, retinyl isostearate, retinyl nonadecanoate, retinyl arachidonate, retinyl behenate, retinyl linoleate, retinyl oleate, retinyl lactate, retinyl glycolate, retinyl hydroxy caprylate, retinyl hydroxy laurate, retinyl tartarate.
A retinoid may be present in the inventive compositions in an amount 33 to 330,000 IU per gram of the composition, preferably 330 to 16,500 IU, most preferably 1,650 to 6,600 IU.
The inventive compositions are preferably essentially free of mineral oil, since the ability of the inventive composition to control sebum production would be decreased or eliminated in the presence of mineral oil.
Sunscreens include those materials commonly employed to block ultraviolet light. Illustrative compounds are the derivatives of PABA, cinnamate and salicylate. For example, avobenzophenone (Parsol 1789(copyright)) octyl methoxycinnamate and 2-hydroxy4-methoxy benzophenone (also known as oxybenzone) can be used. Octyl methoxycinnamate and 2-hydroxy4-methoxy benzophenone are commercially available is under the trademarks Parsol MCX and Benzophenone-3, respectively. The exact amount of sunscreen employed in the compositions can vary depending upon the degree of protection desired from the sun""s UV radiation.
Many cosmetic compositions, especially those containing water, must be protected against the growth of potentially harmful microorganisms. Preservatives are, therefore, necessary. Suitable preservatives include alkyl esters of p-hydroxybenzoic acid, hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. Particularly preferred preservatives of this invention are methyl paraben, propyl paraben, phenoxyethanol and benzyl alcohol. Preservatives will usually be employed in amounts ranging from about 0.1% to 2% by weight of the composition.
The composition according to the invention is intended primarily as a product for topical application to human skin, especially as an agent for controlling or preventing excessive sebum secretion.
In use, a quantity of the composition, for example from 1 to 100 ml, is applied to exposed areas of the skin, from a suitable container or applicator and, if necessary, it is then spread over and/or rubbed into the skin using the hand or fingers or a suitable device.
The cosmetic skin composition of the invention can be in any form, e.g. formulated as a toner, gel, lotion, a fluid cream, or a cream. The composition can be packaged in a suitable container to suit its viscosity and intended use by the consumer. For example, a lotion or fluid cream can be packaged in a bottle or a roll-ball applicator or a propellant-driven aerosol device or a container fitted with a pump suitable for finger operation. When the composition is a cream, it can simply be stored in a non-deformable bottle or squeeze container, such as a tube or a lidded jar. The invention accordingly also provides a closed container containing a cosmetically acceptable composition as herein defined.
The composition may also be included in capsules such as those described in U.S. Pat. No. 5,063,057, incorporated by reference herein.